Rocket-propelled, remote control aerodynamic bodies are caused to roll about their longitudinal axis at launch through grooves in the launching device or through surfaces employed during its flight to compensate for construction inaccuracies and attain a certain degree of longitudinal axis stability.
However, in contrast to the advantage resulting from the aerodynamic body rolling, the activation of the aerodynamic body steering device by means of steering commands necessitates taking into account the instantaneous angular position of the aerodynamic body's steering surface or, for single control member applications, its angular component.
The simplest solution to this requirement appears to be the transformation of the steering signals given in cartesian coordinate system to a polar coordinate system. Coordinate converters have, until now, proved to be very costly regarding power consumption, space requirement and manufacturing cost.
Since the aerodynamic bodies are expendible devices, an aerodynamic body and also a coordinate converter are lost with each launch. To avoid the loss of the coordinate converter, steering techniques for the aerodynamic body bave been developed which develop roll position information through the gyrostabilizer or similar instrumentation and which is transmitted in real time to a ground tracking station to readily carry out the coordinate transformation there. The steering commands expressed in the polar coordinate system are then transmitted back to the aerodynamic body where they can become effective in a proper phase relationship.
In addition to the disadvantage that this technique is not applicable to aerodynamic bodies with a defined preprogrammed flight path, the aerodynamic body must be supplied with its own on-board transmitter. Consequently the possibility for external interference with the aerodynamic body's steering is increased. Moreover the cost in terms of weight, power and expense, of the transmitter installation applied.
In an additional technique, the proper phase effectiveness of the steering command is achieved by communicating a steering command only at the given time when the steering mechanism of the rolling aerodynamic body has the correct altitude. A coordinate converter is no longer necessary through this simple measure. To be sure, the limits of this second technique lie in the relatively sluggish steering. An aerodynamic body which for example moves with a velocity of 600 meters/second and has a roll frequency of 5 hertz would, according to this technique, be able to execute a steering maneuver in a specific direction only once every 120 meters of its trajectory. The steering sluggishness can lead to a reduction of mission success for particular aerodynamic body tasks, i.e., in combat with other high speed steerable aerodynamic bodies or aircraft.
It is an object of the invention to provide a device which can provide continuous coordinate transformation within the aerodynamic body in a simple and cost effective manner and which makes it possible to issue, at any desired time of the aerodynamic body's flight, steering commands which are immediately effective and correct with respect to roll position.